Application of an Alginate–Chitosan Edible Film on Figs (Ficus carica): Effect on Bioactive Compounds and Antioxidant Capacity

Abstract

The main aim of this study was to evaluate the effect of the application of an alginate–chitosan (A–Ch) coating on the bioactive compounds and the antioxidant capacity of fresh figs (Ficus carica), collected at two maturity stages (referred to as stages III and IV), and stored for 15 days at 6 °C. The composition of the internal atmosphere of the figs, as well as the polyphenol content and antioxidant capacity, was analyzed at 0, 3, 6, 9, 12, and 15 days, respectively. The sensory quality of coated and uncoated figs, stored for 15 days, was also assessed. Fresh figs were used as a reference in the sensory quality evaluation. The A–Ch coating caused considerable modifications in the internal atmosphere of the figs at the two maturity stages evaluated. The ripening process was delayed as O2 was reduced and CO2 concentrations were increased. Further, the total polyphenol content of the figs and, also, identified individual polyphenols, were preserved by the application of the A–Ch coating. Anthocyanins, in particular cyanidin-3-O-rutinoside, were the most abundant bioactive compound. Uncoated figs also exhibited higher antioxidant capacity than coated figs at maturity stage III, whereas in coated figs antioxidant capacity was kept constant along storage period regardless of their maturity stage. Interestingly, the coated figs stored for 15 days at 6 °C showed a high acceptability in the sensory evaluation, being similar to fresh figs. Therefore, the A–Ch coating could be an excellent post-harvest technology useful in preserving not only the organoleptic and sensory attributes but also bioactive components of figs during storage at low temperature.